How much does it cost to fix Alpha error code Neon B?

Typical repair cost for the Alpha Neon B fault is £120-250 including labour.

Neon B High

Alpha Neon B Fault Code

Q: What does the Alpha Neon B fault code mean?

Your boiler has automatically shut down because it detected that it was getting too hot, likely to prevent internal damage.

Also written as NEONB — same fault.

The Alpha Neon B fault code means: your boiler has automatically shut down because it detected that it was getting too hot, likely to prevent internal damage.. It appears on 1 Alpha model in our database.

Technical description: Flashing on and off - Overheat thermostat has operated. Rotate selector switch to the reset position (3) to reset.

Typical repair cost £120-250 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Alpha models that show the Neon B fault code

Click a model for the full fault code list and model-specific repair notes.

Cd25 Repair: £120-250

Source

Alpha Neon B fault code information on this page is sourced and cross-checked against the official Alpha service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026